Shock absorber



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II I v /z////// /z Cum Patented Aug. 15, 1944 SHOCK ABSORBER George Binet Dorey, Westmount, Quebec, Canada Application June 9, 1942, Serial No. 446,387

8 Claims.

My invention relates to an improved shock absorber having friction elements in association with a coiled helical spring to dampen excessive oscillations of the spring and to provide means whereby said friction elements will have great shock absorbing capacity and yet be positive in release.

One of the objects of the invention is the provision of an improved shock absorber having a coiled spring and friction elements associated therewith in such a manner that th friction elements will be self alining under all conditions.

A particular object of my invention is to provide a construction wherein the friction elements will engage smoothly throughout the entire range of the travel of the shock absorber and wherein the degree of friction between the various elements will be definitely regulated by the spring pressure.

A further object of my invention is to provide a shock absorber having the wearing parts formed of cheap and readily obtainable materials.

Other advantages of the invention will appear from the following description taken from the accompanying drawing in which:

Fig. 1 is a side elevational view of my improved shock absorber.

Fig. 2 is a vertical transverse sectional view of the structure shown in Fig. 1 and as viewed on a line 2-2 of said Fig. 1.

Fig. 3 is a horizontal sectional view taken on a line 3-3 of Fig. 2.

Fig. 4 is a perspective view of one of the bell crank friction levers.

Fig. 5 is a perspective view of one of the friction shoes.

My invention is shown, by way of illustration, as applied in connection with a helical spring of the type usually employed in railway car trucks and the like.

Referring now to the drawing, my improved construction includes a coiled helical spring A; a pair of bell crank levers 13-43; a pair of friction shoes C-C, said shoes being pivotally associated with the bell crank levers for limited pivotal movement; a pair of friction shell members DD and a bearing plate E.

Each bell crank lever B includes an arm l0 extending within the spring and an arm H extending laterally beyond the outer circumference of the spring in order to receive the spring presupper portion of the arm Ill isformed with a concentrically shaped section l2 which registers longest lateral arm possible. The upper surface sure at an appreciable distanc from the axial center or the spring and thus assure a positive overbalancing action on each bell crank. 'The of the arm H is curved at its outer end as indlcated at It.

Each friction shoe 0 is preferably in the form of a segment of a cylinder having its outer convex surface l1 engaging a similarlycurved concave surface it formed on the interior surface of friction shell D.

The pair of friction shells DD each include a portion in the form of a laterally extending shoulder I! which engages one end of the spring and a body portion 20 extending within the spring. The body portion 20 is cylindrical in shape in the form of a segment of a circle presenting an exterior surface 2| engaging the inner surface 22 of the spring. The inner surface l8 of each shell D is slightly inclined relatively to the axial center of the spring as indicated at 23 to form a wedge shaped opening or pocket between the pair of shell members, said pocket having its narrowest portion adjacent the end of the spring. The tapered pocket so formed by the inclined walls 23 has the effect of forcing the shoes C--C transversely towards each other as the shock absorber is compressed.

The outer longitudinally extending edges of the shell members D are substantially parallel to the direction of movement of the shoes and said edges 24 constitute guiding means for guiding lugs 25 formed on the shoes C. The lugs 25 serve to maintain the shoes and bell crank levers in a definite axial relation to the friction shells while permitting relative longitudinal movement.

The bearing plate E includes a fiat body portion 26 presenting an upper surface 21 in engagement with one end of the spring and an under surface 28 engaging the curved end II of the bell crank arm II. The plate is formed with a circular centering portion 28 extending within the spring and serving to centralize the latter with respect to the plate.

Said plate E is reinforced with downwardly extending side flanges ill-2| which in co-operation with the body portion 20 combine to present a channel shaped section. The channel section so formed straddles the laterally extending portions of the bell crank levers B and serves to strengthen the body portion 28 of the plate.

Each shoe C-C adjacent the concave bearing i3 is each provided with lugs as indicated at 3i and 32 respectively, the latter being extended through an opening 33 formed adjacent the free end of the bell crank arm is. Said lugs 3i and 32 are formed of relatively thin material and are deformed as indicated at at to bend over the section It of the lever and thereby retain the shoes and levers in definite pivotal relation with each other.

The curved surface it of each lever rests on a plane surface or fiat plate which is conventionally indicated by a line it in Fig. 2 of the drawing. The bearing contact of the lever B on the plane surface 35 is preferably located immediately adjacent the center of the spring and the axial center of the section 52 lies outwardly from the said bearing contact location and thus the arms it of the said levers may be considered as struts with the line of thrust along inclined lines as. The inclined relation of these so-called strut members is such that pressure applied in a shoes and shells are preferably formed of malleable iron. the latter having the advantage of cheapness and lightness and are readily obtainable. In connection with the shoes, the ductility of malleable iron is advantageous in providing a 'itlcations which come within the scope of the lengthwise direction on the sections i2 increases the gripping action between the shoes and friction shell members as the shock absorber is compressed. As the pair of friction shells are contained within the coil spring, it will be understood that the lateral thrust of the shoes is finally taken by the spring and therefore the shell walls may be made of comparatively thin and cheap material.

In the' operation of the shock absorber, when pressure is applied to compress the spring, the friction shells D-D by reason of the inclined surfaces is combine to present a wedge shaped member acting on the friction shoes E-E to force the shoes transversely inwardly towards each other. Compression of the spring thus induces a squeezing action on the shoes and this movement in turn is communicated to the bell crank levers which results in the upper ends of arms ill being squeezed together. Relative ap proach of the upper ends of arms it of the levers results in an upward movement of the outer ends of the lateral arms it which forces the plate E upwardly and so compresses the spring from the lower end of the shock absorber.

During movement of the spring there is a slight rocking action of curve is on the plane surface 35 and also a slight sweeping contact be-f tween curved surface it of the arm ii and the undersurface 28 of the plate E. The ever changing contacts made between the levers and their l associated elements contribute in delaying the movement of the spring and thus avoids sudden and violent spring rebound such as occurs when the spring is free to oscillate freely.

The release of the device is the reverse opera.-

tion to that above described as consequent on the expansion of the spring the pressure of the spring maintains the shoes in close frictional engagement with the shells and the parts are smoothly and gradually returned to normal position. The tapered relation between the interior and exterior surfaces of the shells prevent sticking of the shoes while still providing a retarding influence between the exterior of the shells and the spring.

In carrying out my invention, I prefer to make the bell crank levers from forgingsand these lend themselves to drop forged members whereas the claims appended hereto.

What I claim is:

1. In a shock absorber, a coiled helical spring; a friction shell having a body portion extending lengthwise of the spring and a shoudered section engaging one end of the spring; a pair of friction shoes in sliding engagement with the body portion of the shell; and a pair of hell crank levers each having one arm extending lengthwise of the body portion of the shell and having another arm extending laterally from the first mentioned arm; said first named arm pivotally engaging a friction shoe and said lateral arm being extended to engage with the end of the spring opposite to the shouldered section of the friction shell whereby the bell crank levers will force the shoes outwardly against the friction shell body portion on pressure being appliedon the ends of the shock absorber.

2. In a shock absorber, a coiled helical spring, friction elements within the spring including friction shoes; means for spreading the shoes including a pair of hell crank levers each having a laterally extending arm projecting outwardly beyond the coil spring at one end thereof; and a plate interposed between the said lateral arms of the lever and the coil spring, said plate having its bearing contact outwardly beyond the outer circumference of the spring.

3. In a shock absorber, a coiled helical spring; oppositely movable friction elements mounted within the spring, one set of said friction elements consisting of a split shell having a body portion extending lengthwise within the spring and bearing against the inner circumference of the spring, said elements having a shouldered portion bearing against one end of the spring,

said other set of friction elements including slidwith; and a plate interposed between the said lateral arm and the spring, said plate having side reinforcing flanges straddling the lateral arms of the lever, said plate having a circularly shaped centering projection lying within the spring.

4. In a shock absorber, a coiled helical spring; oppositely extending friction elements extending within the spring, said respective mtsof friction elements having portions engaging the opposite ends of the spring; one set of said elements including a split shell reacting against the inner surface of the coiled spring and the other set of said elements including friction shoes slidably engaging the friction shell elements and bell crank levers pivotally associated with the said shoes, each said bell crank lever having one arm extending laterally beyond the spring; and a bearingplate extending beyond the spring to engage the outer end of said laterally projecting assures 3 portion of the lever, said'plate being interposed between the spring andthe lever.

5; In a shock absorber, acoiied spring; $818- 7 scoping. friction elements within the spring; said friction elements including a two part shell hava 5' ing a shouldered portion in engagement with one end of the spring and each'having a body portion within the spring, said body portion being in'the form of a segment'of a circle; friction shoes slidingly engaging the friction shell; meansfor guidi0 ing the shoes relatively to the friction shell and preventing relative circular displacement of the shoes and friction shell while permitting length- 1 wise sliding movement, said means including lugs on the shoes engaging with the edge portions of the friction shell members; and means for forcing the shoes into engagement with the friction shell members, said means including :a pair of bell crank levers, each having an arm engaging a shoe and having another arm reacting against the opposite end of the spring.

6. In a shock absorber, a coiled spring; a

shouldered two part friction shell engaging one end of the spring and having a body portion extending lengthwise within the spring, said body portion having shoes in sliding engagement therewith, said body portion being in the form 'of a segment of a circle and having its outersurface bearing against the inner circumference of the spring; said surface of the shell engaging the shoe being slightly inclined to the axial center of the spring in a direction to, cause relative squeez- 1 ing of the shoes on compression of the spring; 'means resisting relative approachment of the pair of shoes, said means including bell crank levers each having an arm in pivotal engagement with a shoe and having another arm extending laterally to react against the end of the spring opposite to, that engaged by the friction shell.

. 7. In a shock absorber, a coiled spring; a

shouldered two part friction shell having the shouldeinengaging an end of the spring and a body portion extending lengthwise within the spring, said body portion bearing against the inner face of the spring, a friction surface on each body ,portion, said' friction surface extending lengthwise of the spring at a slight angle to the axial center of the spring whereby the friction surfaces of the two parts of the friction shell combine to present a flared pocket with its narrowest portion adjacent the shouldered part of the shell; friction shoes movable in the said pocket; and means for maintaining the shoes in close frictional contact with the shell and resisting relative transverse movement of said shoes as the shock absorber is compressed and the shoes are forced inwardly in the narrowing pocket, said means including a pair of bell crank levers each having an arm in pivotal association with one of the shoes and having another arm extended laterally to reactagainst' the end of the spring opposite to that engaged by the shouldered portion of the shell.

8. In a shock absorber, a coiled spring; a two part shoulderedfriction shell including a body portion within the spring and having the shouldered portion engaging one end of the spring;

,shoes in sliding engagement with ,the shell;

means for, forcing the shoes against the shell, said means including a pair of strut like members pivotally engaging at one end the shoes, and at the opposite end presenting a seat for one end of the shock absorber, said seats of the pair-of struts being spaced inwardly laterally from the associated shoe pivots whereby pressure from the shoes to the seats will extend along lines inclined relatively to the axial center of the shock absorber; and lateral extensions from each strut engaging the end of the spring opposite to that engaged by the shouldered section of the shell.

BINET DOREY. 

